Free flow test methods are generally simple to perform and provide a clear, direct result. The slump test is the best known of the free flow test methods. Other free flow test methods represent attempts to improve on the slump test. Free flow tests generally give a result that is closely related to yield stress. A few tests have been improved to measure plastic viscosity also.
Although many of the free flow tests can be used on concretes with a wide range of workability, none of the free flow tests features vibration. Tests that do not include vibration may not be themost appropriate test methods for characterizing low workability and highly thixotropic concrete mixtures.
